Package structure and method for manufacturing the same

ABSTRACT

A package structure and its manufacturing method are provided. The package structure includes a substrate with a recess, and a first MEMS chip, a first intermediate chip, a second MEMS chip and a first capping plate sequentially formed on the substrate. The lower surface of the first MEMS chip has a first sensor or a microactuator. The upper surface of the second MEMS chip has a second sensor or a microactuator. The first intermediate chip has a through-substrate via, and includes a signal conversion unit, a logic operation unit, a control unit, or a combination thereof. The package structure includes at least one of the first sensor and the second sensor.

CROSS REFERENCE TO RELATED APPLICATIONS

This Application claims priority of Taiwan Patent Application No.109144042, filed on Dec. 14, 2020, the entirety of which is incorporatedby reference herein.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a package structure, and in particularit relates to a package structure with a three-dimensionalmicroelectromechanical system chip stack and a manufacturing methodthereof.

Description of the Related Art

The microelectromechanical system (MEMS) is a technology that combinesmicroelectronic technology and mechanical engineering. MEMS technologyenables a lot of industrial equipment to be miniaturized. MEMS devicesusually include a microprocessor and at least one microsensor forobtaining external information.

For current MEMS devices, it is usually to assemble multiple MEMSelements in the same package structure, and it is necessary to integratethe operations of these MEMS elements. However, if the two MEMS elementsare too close, the signals of the two MEMS elements may interfere witheach other. As a result, the yield and reliability of the MEMS devicewill be reduced.

On the other hand, in the package structure of MEMS devices, each MEMSelement is usually independent and needs to be controlled by its owncontrol chip. Furthermore, additional controlling units or computingunits are usually required to integrate or process signals fromdifferent MEMS elements. Therefore, the area of the MEMS device isrelatively large, which is disadvantageous to the miniaturization of thepackage structure.

Therefore, in the technical field, there is still a need for a MEMSdevice package structure and a manufacturing method thereof with highyield and high reliability.

BRIEF SUMMARY OF THE INVENTION

The embodiments of the present invention provide a package structure anda method for manufacturing a package structure, which can improve theyield and reliability of the MEMS device, and can facilitate theminiaturization of the package structure.

In accordance with some embodiments of the present disclosure, a packagestructure is provided. The package structure includes a substrate, afirst MEMS chip, a first intermediate chip, a second MEMS chip, and afirst capping plate. The substrate has a recess. The first MEMS chip isformed on the substrate, and has a through-substrate via. The lowersurface of the first MEMS chip has a first sensor or a microactuator,and the first sensor or the microactuator is located in the recess. Thefirst intermediate chip is formed on the first MEMS chip, and has athrough-substrate via. The first intermediate chip comprises a signalconversion unit, a logic operation unit, a control unit, or acombination thereof The second MEMS chip is formed on the firstintermediate chip, and has a through-substrate via. The upper surface ofthe second MEMS chip has a second sensor or a microactuator. The packagestructure comprises at least one of the first sensor and the secondsensor. The first capping plate is formed on the second MEMS chip, andprovides a receiving space. The second sensor or the microactuatorlocated on the upper surface of the second MEMS chip is located in thereceiving space.

In accordance with some embodiments of the present disclosure, a methodfor manufacturing a package structure is provided. The method includesproviding a substrate, and the substrate has a plurality of recesses.The method includes forming a plurality of first MEMS chips on thesubstrate, and each first MEMS chip has a through-substrate via. Thelower surface of each first MEMS chip has a first sensor ormicroactuator, and the first sensor or the microactuator is located inone of the recesses. The method includes forming a plurality of firstintermediate chips on the substrate, and each first intermediate chip isrespectively formed on one of the first MEMS chips. Each firstintermediate chip has a through-substrate via, and each firstintermediate chip comprises a signal conversion unit, a logic operationunit, a control unit, or a combination thereof. The method includesforming a plurality of second MEMS chips on the first intermediatechips, and each second MEMS chip has a through-substrate via. The uppersurface of each second MEMS chip has a second sensor or a microactuator.The package structure comprises the first sensor and/or the secondsensor. The method includes forming a plurality of first capping plateson the second MEMS chips, and each first capping plate provides areceiving space. The second sensor or the microactuator located on theupper surface of each second MEMS chip is located in the receivingspace.

In the package structure with the MEMS device provided by theembodiments of the present invention, at least one intermediate chip isdisposed between two vertically stacked MEMS chips. Because the distancebetween the two MEMS chips is increased by disposing the intermediatechip, the signal interference between the MEMS chips can be reduced.Therefore, the yield and reliability can be improved, and theminiaturization of the package structure can be facilitated. Inaddition, in the embodiments of the present invention, more than threeMEMS chips with different functions can be integrated in the samepackage structure without significantly increasing the area of thepackage structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A to FIG. 1F are cross-sectional views corresponding to varioussteps of manufacturing a package structure in accordance with someembodiments of the present invention.

FIG. 2 is a cross-sectional view of a package structure in accordancewith other embodiments of the present invention.

FIG. 3 is a cross-sectional view of a package structure in accordancewith other embodiments of the present invention.

FIG. 4 is a cross-sectional view of a package structure in accordancewith other embodiments of the present invention.

FIG. 5 is a cross-sectional view of a package structure in accordancewith other embodiments of the present invention.

FIG. 6 is a cross-sectional view of a package structure in accordancewith other embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure is best understood from the following detaileddescription when read with the accompanying figures. Furthermore, thepresent disclosure may repeat reference numerals and/or letters in thevarious examples. This repetition is for the purpose of simplicity andclarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

A package structure and a method for manufacturing such a packagestructure are provided in the embodiments of the present invention. FIG.1A to FIG. 1F are cross-sectional views corresponding to various stepsof manufacturing a package structure 100 in accordance with someembodiments of the present invention.

Referring to FIG. 1A, a substrate 102 having a plurality of recesses 105is provided. Then, corresponding to the positions of the recesses 105, aplurality of first MEMS chips 110 are formed on the substrate 102. Thematerial of the substrate 102 may include glass, polymer, semiconductor,metal, or a combination thereof. A suitable substrate 102 may beselected according to the function of the first MEMS chip 110. Forexample, when the first MEMS chip 110 includes an optical sensor, thematerial of the substrate 102 may be the material with transparency,such as glass or polymer.

The first MEMS chip 110 may be formed by any suitable method. Forexample, through-holes may be formed in the semiconductor wafer by alithography process, an etching process, a laser drilling process, amechanical drilling process, or a combination thereof. Then, aconductive material is filled into the through hole to form athrough-substrate via (TSV) 114. For example, the through-substrate via114 may be a through-silicon via. Then, a first microstructure 111 isformed on one surface of the semiconductor wafer. Then, thesemiconductor wafer may be cut to form a plurality of first MEMS chips110. In some embodiments, the first MEMS chip 110 may be bonded to thesubstrate 102. For example, the substrate 102 and the first MEMS chip110 may be bonded together by an adhesive which is applied to the uppersurface of the substrate 102 or the lower surface of the first MEMS chip110.

As shown in FIG. 1A, the lower surface of the first MEMS chip 110 has afirst microstructure 111, and each first MEMS chip 110 has a pluralityof through-substrate vias 114 therein. The first microstructure 111 maybe a sensor or a microactuator. In one embodiment, the firstmicrostructure 111 is a first sensor, such that the first MEMS chip 110has a sensing function. In another embodiment, the first microstructure111 is a microactuator, and the first MEMS chip 110 has functions suchas switching, deformation, or movement. In order to simplify thedescription, the forming method and function of the first microstructure111 will not be described in detail herein. The conductive material thatcan be used to form the through-substrate via 114 may include metals(for example, copper, aluminum, silver, gold, tungsten, cobalt, nickel,titanium, or tantalum), alloys, or a combination thereof.

Referring to FIG. 1A, after the substrate 102 and the first MEMS chip110 are bonded together, a molding compound layer 151 is formed to coverthe substrate 102 and the first MEMS chip 110. Then, the moldingcompound layer 151 is cured. Next, a first planarization process, suchas a chemical mechanical polishing (CMP) process, is performed to exposethe upper surfaces of the first MEMS chip 110 and the through-substratevia 114. The first planarization process makes the upper surfaces of thefirst MEMS chip 110, the through-substrate via 114, and the moldingcompound layer 151 coplanar to facilitate the formation of thesubsequent first redistribution layer 161. The molding compound layer151 can provide a good supporting function and protect the first MEMSchip 110 from damage. The molding compound layer 151 may include acurable resin (for example, polyester resin, vinyl ester resin, or epoxyresin) or a combination thereof The molding compound layer 151 may becured by light or heating.

Referring to FIG. 1B, a first redistribution layer 161 is formed on thefirst MEMS chip 110. Then, a plurality of first intermediate chips 120are formed on the first redistribution layer 161. The position of thefirst intermediate chip 120 corresponds to the position of the firstMEMS chip 110. The first redistribution layer 161 may include a stackedstructure formed by a plurality of insulating layers and a plurality offirst conductive elements 161 a formed in the stacked structure. In someembodiments, the first redistribution layer 161 may also includeelectrical connecting elements 171 as needed, so that the firstintermediate chip 120 can be electrically connected to the firstconductive element 161 a. In the present embodiment, the electricalconnecting elements 171 are formed on the upper surface of the firstredistribution layer 161. In other embodiments, the electricalconnecting element 171 is formed in the first redistribution layer 161and is exposed from the upper surface of the first redistribution layer161 or partially protrudes from the upper surface of the firstredistribution layer 161. The first conductive elements 161 a mayinclude conductive lines, conductive vias, or conductive pads. Thematerial of the insulating layer may include resin (for example,polyimide resin or epoxy resin), silicon oxide, silicon nitride, siliconoxynitride, or a combination thereof The electrical connecting elements171 may include conductive pillars or conductive solder balls. Thematerial of the first conductive element 161 a may include metal (forexample, copper, aluminum, silver, gold, tungsten, cobalt, nickel,titanium, or tantalum), alloy, or a combination thereof. The meltingpoint of the electrical connecting element 171 may be lower than themelting point of the first conductive element 161 a. The material of theelectrical connecting element 171 may include metal (for example,copper, aluminum, silver, gold, tin, or lead), alloy, or a combinationthereof.

The first redistribution layer 161 may be formed by repeating adeposition process, a patterning process, and a planarization processseveral times. For example, an insulating layer may be formed on themolding compound layer 151 and the first MEMS chip 110 by a depositionprocess. Then, openings or trenches may be formed in the above-mentionedinsulating layer by a patterning process. Then, a conductive materialmay be formed in the above-mentioned openings or trenches by adeposition process. Then, the upper surface of the insulating layer andthe upper surface of the conductive material may be made coplanar by aplanarization process. The above-mentioned steps are repeated severaltimes, so that the first redistribution layer 161 can be formed. Thedeposition process may include 3-D printing (laminated manufacturing),physical vapor deposition, chemical vapor deposition, atomic layerdeposition, spin coating process, or a combination thereof. Thepatterning process may include a lithography process, an etchingprocess, laser or mechanical drilling processes, or a combinationthereof. The planarization process may include a CMP process, amechanical polishing process, or a combination thereof.

Referring to FIG. 1B, the first intermediate chip 120 has a plurality ofelectrical connecting elements 122 and a plurality of through-substratevias 124. The electrical connecting element 122 is formed on the lowersurface of the first intermediate chip 120 and is electrically connectedto the electrical connecting element 171. The material and formingmethod of the electrical connecting element 122 may be the same as orsimilar to the material and forming method of the electrical connectingelement 171. The electrical connecting element 122 can be joined to theelectrical connecting element 171 or the first conductive element 161 a(if the electrical connecting element 171 does not exist) by heatingtreatment. As a result, the first intermediate chip 120 can be fixed onthe first redistribution layer 161.

Referring to FIG. 1C, after the first intermediate chip 120 is bonded tothe first redistribution layer 161, a molding compound layer 152 isformed to cover the first intermediate chip 120. Then, the moldingcompound layer 152 is cured. Next, a second planarization process, suchas a CMP process, is performed to expose the upper surface of the firstintermediate chip 120 and the upper surface of the through-substrate via124. The second planarization process makes the upper surface of thefirst intermediate chip 120, the upper surface of the through-substratevia 124, and the upper surface of the molding compound layer 152coplanar to facilitate the formation of the subsequent secondredistribution layer 162.

In one embodiment, the second redistribution layer 162 may be formed onthe first intermediate chip 120. The second redistribution layer 162 mayinclude a stacked structure formed by a plurality of insulating layersand a plurality of second conductive elements 162 a formed in thestacked structure. In some embodiments, the second redistribution layer162 may also include electrical connecting elements 172 as needed, sothat the second conductive elements 162 a can be electrically connectedto the second MEMS chip 130 formed subsequently. The structure,material, and forming method of the second redistribution layer 162 maybe the same as or similar to the structure, material, and forming methodof the first redistribution layer 161, and will not be described indetail herein.

Referring to FIG. 1D, second MEMS chips 130 are formed on the firstintermediate chips 120. Then, first capping plates 104 are formed on thesecond MEMS chips 130. Each first capping plate 104 is used to provide areceiving space 107.

The material of the first capping plate 104 may be the same as orsimilar to the material of the substrate 102. A suitable first cappingplate 104 may be selected according to the function of the second MEMSchip 130. For example, when the second MEMS chip 130 includes a gassensor, the material of the first capping plate 104 may be thechemically passivated material, such as glass or polymer.

As shown in FIG. 1D, the lower surface of the second MEMS chip 130 has aplurality of electrical connecting elements 132, and each second MEMSchip 130 has a plurality of through-substrate vias 134 therein. Theelectrical connecting element 132 of the second MEMS chip 130 may bejoined to the electrical connecting element 172 or the second conductiveelement 162 a (if the electrical connecting element 172 does not exist)by heating treatment. As a result, the second MEMS chip 130 can be fixedon the second redistribution layer 162.

As shown in FIG. 1D, the upper surface of each second MEMS chip 130 hasa second microstructure 131 and a plurality of conductive pads 135. Theconductive pad 135 may be used to electrically connect with an externalcircuit. The material and forming method of the conductive pad 135 maybe the same as or similar to the material and forming method of thefirst conductive element 161 a. The second microstructure 131 may be asensor or a microactuator. In one embodiment, the second microstructure131 is a second sensor, and the second MEMS chip 130 has a sensingfunction. In another embodiment, the second microstructure 131 is amicroactuator, and the second MEMS chip 130 has functions such asswitching, deformation, or movement.

The forming method of the second MEMS chip 130 may be the same as orsimilar to the forming method of the first MEMS chip 110. In the presentembodiment, the second MEMS chip 130 is fixed on the secondredistribution layer 162 first. Then, the first capping plate 104 andthe second MEMS chip 130 are bonded together by an adhesive. In otherembodiments, the first capping plate 104 and the second MEMS chip 130are bonded together first, and then, the first capping plate 104 and thesecond MEMS chip 130 are fixed on the second redistribution layer 162.

Referring to FIG. 1D, after the second MEMS chip 130 is fixed on thesecond redistribution layer 162, an underfill layer 180 is formedbetween the second MEMS chip 130 and the second redistribution layer162. The underfill layer 180 may include a curable resin (for example,epoxy resin). The underfill layer 180 can prevent the second MEMS chip130 from being displaced or falling off, and can prevent the electricalconnecting element 132 and the electrical connecting element 172 frombeing oxidized.

Please refer to FIG. 1E, at a position between two adjacent firstcapping plates 104, a cutting process 190 is performed on the firstredistribution layer 161, the molding compound layer 151, the secondredistribution layer 162, the molding compound layer 152, and thesubstrate 102 to separate the package structures 100 from each other.The cutting process 190 may include a laser cutting process, a diamondcutting process, or a combination thereof.

Referring to FIG. 1F, an electrical connecting component 182 is formedto electrically connect the conductive pad 135 and an external circuit.In some embodiments, the electrical connecting component 182 is aconductive circuit, and the electrical connecting component 182 isbonded to the conductive pad 135 exposed outside the first capping plate104 by a wire bonding process. After the electrical connectingcomponents 182 are formed, other conventional manufacturing processesmay be subsequently performed to complete the package structure 100.

In the manufacturing method of the package structure 100 provided in thepresent embodiment, the substrate 102 with the recess 105 is bonded tothe first MEMS chip 110, and a cutting process 190 is used to separatethe package structures 100. In other words, in the present embodiment,there is no need to use an additional carrier substrate to temporarilysupport the MEMS chip as in the conventional technique. Therefore, thesubsequent step of removing the carrier substrate can be omitted.Furthermore, in the present embodiment, after the cutting process 190,there is no need to form a capping plate to cover the MEMS chip as inthe conventional technique. Therefore, the manufacturing method providedby the present embodiment can simplify the manufacturing process.

The embodiments of the present invention provide a package structure100. Referring to FIG. 1F, the package structure 100 includes asubstrate 102, a first MEMS chip 110, a first redistribution layer 161,a first intermediate chip 120, a second redistribution layer 162, asecond MEMS chip 130, and a first capping plate 104 stacked sequentiallyfrom bottom to top.

The upper surface of the substrate 102 has a recess 105. The lowersurface of the first MEMS chip 110 has a first microstructure 111. Thefirst microstructure 111 is located in the recess 105. The first cappingplate 104 covers the second MEMS chip 130 and provides a receiving space107. The upper surface of the second MEMS chip 130 has a secondmicrostructure 131. The second microstructure 131 is located in thereceiving space 107. The first microstructure 111 may be a first sensoror a microactuator, and the second microstructure 131 may be a secondsensor or a microactuator. In the present embodiment, at least one ofthe first microstructure 111 and the second microstructure 131 may be asensor. In some embodiments, the first microstructure 111 is a firstsensor, and the second microstructure 131 is a second sensor. In such anembodiment, the first microstructure 111 and the second microstructure131 may each independently be a sound sensor, a gas sensor, an opticalsensor, a temperature sensor, a chemical substance sensor, or an anothersensor. The first intermediate chip 120 is formed between the first MEMSchip 110 and the second MEMS chip 130. The first redistribution layer161 is formed between the first MEMS chip 110 and the first intermediatechip 120, and the second redistribution layer 162 is formed between thefirst intermediate chip 120 and the second MEMS chip 130.

In the package structure 100 having vertically stacked MEMS chipsprovided by the embodiments of the present invention, the firstintermediate chip 120 is disposed between the vertically stacked firstMEMS chip 110 and the second MEMS chip 130. Compared with horizontallyarranging the first MEMS chip 110 and the second MEMS chip 130, thepresent embodiment can increase the distance between the first MEMS chip110 and the second MEMS chip 130 and reduce the area of the packagestructure 100. Therefore, the signal interference between the first MEMSchip 110 and the second MEMS chip 130 can be reduced. As a result, theyield and reliability of the package structure 100 can be improved, andthe miniaturization of the package structure 100 can be facilitated.

In the package structure 100 provided by the embodiments of the presentinvention, the first intermediate chip 120 may include a signalconversion unit, a logic operation unit, a control unit, or acombination thereof. Therefore, the first intermediate chip 120 canreceive and process signals from the first MEMS chip 110 and the secondMEMS chip 130 at the same time, and can control the operations of thefirst MEMS chip 110 and the second MEMS chip 130 at the same time. As aresult, the performance of the package structure 100 can be improved,and the miniaturization of the package structure 100 can be facilitated.

In the package structure 100 provided by the embodiments of the presentinvention, the first redistribution layer 161 can be used to transmitsignals between the first intermediate chip 120 and the first MEMS chip110, and the second redistribution layer 162 can be used to transmitsignals between the first intermediate chip 120 and the second MEMS chip130. The first MEMS chip 110, the first intermediate chip 120, and thesecond MEMS chip 130 may have different sizes. By providing the firstredistribution layer 161 and the second redistribution layer 162, theelectrical connection between adjacent elements can be facilitated. Inother words, the first redistribution layer 161 and the secondredistribution layer 162 help to integrate the first MEMS chip 110, thefirst intermediate chip 120 and the second MEMS chip 130 into the samepackage structure 100.

In the package structure 100 provided by the embodiments of the presentinvention, the structure of the recess 105 and the receiving space 107may be changed according to the function of the first MEMS chip 110 andthe function of the second MEMS chip 130. For example, when the recess105 is a closed space, the first microstructure 111 may be a soundsensor, an optical sensor, a temperature sensor, or an actuator. On theother hand, when the recess 105 is an open space, the firstmicrostructure 111 may be a gas sensor, a chemical substance sensor, oran actuator.

Referring to FIG. 1F, in the present embodiment, the recess 105 is aclosed space. The upper surface of the first capping plate 104 has anopening 101, so that the receiving space 107 becomes an open space. Insome embodiments, a filling medium may be used to fill the recess 105,so that the performance of the first MEMS chip 110 may be furtherimproved by the filling medium. For example, in some embodiments, thefirst microstructure 111 is an optical sensor, and a filling medium withlight absorption characteristics is used to fill the recess 105. Thefilling medium can allow the light in the desired wavelength range topass through, and can block the light in other wavelength ranges.Therefore, the sensing sensitivity can be improved. In addition, inother embodiments, the filling medium can be used to adjust therefractive index, color, or sound absorption characteristics in therecess 105. The filling medium may include curable polymers, pigments,dyes, solvents, high-viscosity liquid materials, or a combinationthereof.

It should be understood that the structure of the recess 105 and thereceiving space 107 may be determined according to needs. For example,the recess 105 and the receiving space 107 can each independently be aclosed space or an open space. The filling medium may be formed in theclosed recess 105 and/or the receiving space 107 as needed.

FIG. 2 is similar to FIG. 1F. In FIG. 2, the same reference numerals areused to denote the same elements as those shown in FIG. 1F. In order tosimplify the description, the elements that are the same as those shownin FIG. 1F and the forming process steps thereof will not be describedin detail here.

The package structure 200 shown in FIG. 2 is similar to the packagestructure 100 shown in FIG. 1F, and the difference is that the packagestructure 200 has a second intermediate chip 220 and a thirdintermediate chip 320. The first intermediate chip 120, the secondintermediate chip 220, and the third intermediate chip 320 may be formedon the first redistribution layer 161 in the process step correspondingto FIG. 1B. In other words, in the present embodiment, the firstintermediate chip 120, the second intermediate chip 220, and the thirdintermediate chip 320 are arranged horizontally.

The structure of the second intermediate chip 220 and the structure ofthe third intermediate chip 320 may be similar to the structure of thefirst intermediate chip 120. The second intermediate chip 220 has aplurality of electrical connecting elements 222 and a plurality ofthrough-substrate vias 224. The third intermediate chip 320 has aplurality of electrical connecting elements 322 and a plurality ofthrough-substrate vias 324. The second intermediate chip 220 may includea memory unit, an antenna unit, or a combination thereof. The thirdintermediate chip 320 may include a memory unit, an antenna unit, or acombination thereof. In some embodiments, one of the second intermediatechip 220 and the third intermediate chip 320 has a memory unit, and theother has an antenna unit. The memory unit can store signals from thefirst MEMS chip 110 and/or the second MEMS chip 130. The antenna unitcan receive signals from the outside or send signals to the outside.Therefore, the packaging structure 200 can be operated remotely.

In the present embodiment, the size of the second intermediate chip 220and the size of the third intermediate chip 320 are smaller to the sizeof the first intermediate chip 120. Furthermore, the size of the secondMEMS chip 130 is larger than the sum of the size of the firstintermediate chip 120, the size of the second intermediate chip 220, andthe size of the third intermediate chip 320. Therefore, even if thesecond intermediate chip 220 and the third intermediate chip 320 areintegrated into the package structure 200, the volume of the packagestructure 200 will not increase. Integrating the second intermediatechip 220 and the third intermediate chip 320 can increase the functionsand application fields of the package structure 200.

FIG. 3 is similar to FIG. 2. In FIG. 3, the same reference numerals areused to denote the same elements as those shown in FIG. 2. In order tosimplify the description, the elements that are the same as those shownin FIG. 2 and the forming process steps thereof will not be described indetail here.

The package structure 300 shown in FIG. 3 is similar to the packagestructure 200 shown in FIG. 2, and the difference is that the secondintermediate chip 220 and the third intermediate chip 320 are formedbetween the second MEMS chip 130 and the first intermediate chip 120.The second intermediate chip 220 and the third intermediate chip 320 maybe respectively formed on the second redistribution layer 162 in theprocess step corresponding to FIG. 1C. Then, a molding compound layer153 is formed to cover the second intermediate chip 220 and the thirdintermediate chip 320. Then, the molding compound layer 153 is cured.Next, a third planarization process is performed to expose the uppersurface of the second intermediate chip 220, the upper surface of thethird intermediate chip 320, and the upper surfaces of thethrough-substrate vias 224, and the upper surfaces of thethrough-substrate vias 324. Therefore, the upper surface of the secondintermediate chip 220, the upper surface of the third intermediate chip320, the upper surfaces of the through-substrate vias 224, the uppersurfaces of the through-substrate vias 324, and the upper surface of themolding compound layer 153 are coplanar to facilitate the formation ofthe subsequent third redistribution layer 163. Then, the thirdredistribution layer 163 may be formed on the second intermediate chip220 and the third intermediate chip 320, and the second MEMS chip 130may be formed on the third redistribution layer 163. In other words, inthe present embodiment, the second intermediate chip 220 and the thirdintermediate chip 320 are arranged horizontally, and the secondintermediate chip 220 (and the third intermediate chip 320) and thefirst intermediate chip 120 are arranged vertically. The thirdredistribution layer 163 may include a stacked structure formed by aplurality of insulating layers and a plurality of third conductiveelements 163 a formed in the stacked structure. In some embodiments, thethird redistribution layer 163 may also include electrical connectingelements 173 as needed, so that the third conductive element 163 a canbe electrically connected to the second MEMS chip 130.

In the present embodiment, the distance between the first MEMS chip 110and the second MEMS chip 130 can be further increased. Therefore, thesignal interference between the first MEMS chip 110 and the second MEMSchip 130 can be further reduced. As a result, the yield and reliabilityof the package structure 300 can be further improved.

FIG. 4 is similar to FIG. 3. In FIG. 4, the same reference numerals areused to denote the same elements as those shown in FIG. 3. In order tosimplify the description, the elements that are the same as those shownin FIG. 3 and the forming process steps thereof will not be described indetail here.

The package structure 400 shown in FIG. 4 is similar to the packagestructure 300 shown in FIG. 3, and the difference is that the secondintermediate chip 220 and the third intermediate chip 320 are formedbetween the first MEMS chip 110 and the first intermediate chip 120. Thesecond intermediate chip 220 and the third intermediate chip 320 may berespectively formed on the first redistribution layer 161 in the processstep corresponding to FIG. 1B. Then, the second redistribution layer 162may be formed on the second intermediate chip 220 and the thirdintermediate chip 320, and the first intermediate chip 120 may be formedon the second redistribution layer 162. Next, a third redistributionlayer 163 may be formed on the first intermediate chip 120, and a secondMEMS chip 130 may be formed on the third redistribution layer 163.

Similar to the embodiment shown in FIG. 3, in the present embodiment,the distance between the first MEMS chip 110 and the second MEMS chip130 can be further increased. Therefore, the signal interference betweenthe first MEMS chip 110 and the second MEMS chip 130 can be furtherreduced.

It should be understood that the embodiments shown in FIG. 2 to FIG. 4are merely for the purpose of illustration, and are not intended tolimit the present invention. The number, function and arrangement ofintermediate chips may be determined according to needs.

FIG. 5 is similar to FIG. 2. In FIG. 5, the same reference numerals areused to denote the same elements as those shown in FIG. 2. In order tosimplify the description, the elements that are the same as those shownin FIG. 2 and the forming process steps thereof will not be described indetail here.

The package structure 500 shown in FIG. 5 is similar to the packagestructure 200 shown in FIG. 2, and the difference is that the packagestructure 500 further has a third MEMS chip 140. The third MEMS chip 140is formed between the first intermediate chip 120 and the second MEMSchip 130. After the process step corresponding to FIG. 1C, the fourthredistribution layer 164 is formed on the second redistribution layer162, and a plurality of openings exposing the second redistributionlayer 162 are formed in the fourth redistribution layer 164. Then,corresponding to the positions of these openings, a plurality of thirdMEMS chips 140 are formed on the second redistribution layer 162. Then,the second MEMS chip 130 may be formed on the fourth redistributionlayer 164.

The fourth redistribution layer 164 may include a stacked structureformed by a plurality of insulating layers and a plurality of fourthconductive elements 164 a formed in the stacked structure. In someembodiments, the fourth redistribution layer 164 may also includeelectrical connecting elements 174 as needed, so that the fourthconductive element 164 a can be electrically connected to the secondMEMS chip 130.

Referring to FIG. 5, a second capping plate 106 is formed on the thirdMEMS chip 140. The second capping plate 106 provides a receiving space109, and a third microstructure 141 of the third MEMS chip 140 islocated in the receiving space 109. A suitable second capping plate 106may be selected according to the function of the third MEMS chip 140. Inthe present embodiment, after the second capping plate 106 and the thirdMEMS chip 140 are bonded together, the second capping plate 106 and thethird MEMS chip 140 are fixed on the second redistribution layer 162. Inother implementations, the third MEMS chip 140 is fixed on the secondredistribution layer 162 first. After that, the second capping plate 106and the third MEMS chip 140 are bonded together by an adhesive which isapplied to the upper surface of the third MEMS chip 140 or the lowersurface of the second capping plate 106.

As shown in FIG. 5, the lower surface of each of the third MEMS chip 140has a plurality of electrical connecting elements 142, and each thirdMEMS chip 140 has a plurality of through-substrate vias 144 therein. Theelectrical connecting element 142 of the third MEMS chip 140 may bejoined to the electrical connecting element 172 or the second conductiveelement 162 a (if the electrical connecting element 172 does not exist)by heating treatment. As a result, the third MEMS chip 140 can be fixedon the second redistribution layer 162. The upper surface of each thirdMEMS chip 140 has a third microstructure 141. The third microstructure141 may be a sensor or a microactuator. In one embodiment, the thirdmicrostructure 141 is a third sensor, and the third MEMS chip 140 has asensing function. In another embodiment, the third microstructure 141 isa microactuator, and the third MEMS chip 140 has functions such asswitching, deformation, or movement.

In the present embodiment, the sidewall of the second capping plate 106has an opening 101, so that the receiving space 109 is an open space. Inother embodiments, the receiving space 109 is a closed space and may befilled with a filling medium. It should be noted that, in the presentembodiment, when the receiving space 109 is an open space, in order toreduce or avoid the influence of subsequent manufacturing processes onthe third microstructure 141, the opening 101 is located on the sidewallof the second capping plate 106.

FIG. 6 is similar to FIG. 5. In FIG. 6, the same reference numerals areused to denote the same elements as those shown in FIG. 5. In order tosimplify the description, the elements that are the same as those shownin FIG. 5 and the forming process steps thereof will not be described indetail here. The package structure 600 shown in FIG. 6 is similar to thepackage structure 500 shown in FIG. 5, and the difference is that thethird MEMS chip 140 is formed on the first intermediate chip 120 and isarranged horizontally with the second MEMS chip 130. The second MEMSchip 130 and the third MEMS chip 140 may be respectively formed on thesecond redistribution layer 162 in the process step corresponding toFIG. 1D.

In the embodiments shown in FIG. 5 and FIG. 6, more than three MEMSchips with different functions can be integrated in the same packagestructure without significantly increasing the area. Therefore, theapplication fields can be increased under the premise of meeting theminiaturization of the package structure. In addition, the number,functions, and arrangement of MEMS chips may be determined according toneeds.

The various packaging structures with MEMS devices provided by theembodiments of the present invention can be widely used in variousfields. In some embodiments, the packaging structure 100 shown in FIG.1F may be a biomedical detecting device. The first MEMS chip 110 may bea micro motor, and the second MEMS chip 130 may be a sensor of chemicalsubstances (for example, hemoglobin, specific protein or hormone, etc.).In such an embodiment, the packaging structure 100 can move in a livingbody and detect specific chemical substances. In other embodiments, anyone of the packaging structures 200, 300, and 400 may be another type ofbiomedical detecting device. The second intermediate chip 220 may have amemory unit, and the third intermediate chip 320 may have an antennaunit. Any one of the packaging structures 200, 300, and 400 can storethe sensing data of a specific chemical substance and can be operatedremotely or send the sensing data to outside the living body. In otherembodiments, any one of the packaging structures 500 and 600 may beanother type of biomedical detecting device. The third MEMS chip 140 maybe a sensor of the second chemical substance (for example, hemoglobin,specific protein or hormone, etc.). In such an embodiment, any one ofthe packaging structures 500 and 600 can simultaneously detect twospecific chemical substances.

In some embodiments, the packaging structure 100 as shown in FIG. 1F maybe a breathing regulating device. The first MEMS chip 110 may be amicroactuator, and the second MEMS chip 130 may be a sensor of gas (forexample, oxygen or carbon dioxide, etc.). In such an embodiment, thepackaging structure 100 can adjust the supplied oxygen concentration bydetecting the breathed gas concentration data of the patient. In otherembodiments, any one of the packaging structures 200, 300, and 400 maybe another type of breathing regulation device. The second intermediatechip 220 may have a memory unit, and the third intermediate chip 320 mayhave an antenna unit. Any one of the packaging structures 200, 300, and400 can store sensing data of a specific gas, and can send signals toremotely control another gas supply device or send sensing data to otherdevices. In other embodiments, any one of the packaging structures 500and 600 may be another type of breathing regulation device. The thirdMEMS chip 140 may be a sound sensor. In such an embodiment, any one ofthe packaging structures 500 and 600 can simultaneously detect the gasconcentration and the sound of the patient's chest cavity to adjust thesupplied oxygen concentration.

It should be understood that the above-mentioned embodiments are merelyfor the purpose of illustration, and are not intended to limit thepresent invention. The function and combination of the MEMS chip may bedetermined according to actual needs or application fields.

In summary, in the package structure with MEMS device provided by theembodiment of the present invention, at least one intermediate chip isdisposed between two vertically stacked MEMS chips. Because the distancebetween the two MEMS chips is increased by disposing the intermediatechip, the signal interference between the MEMS chips can be reduced.Therefore, the yield and reliability can be improved. Furthermore, theintermediate chip can simultaneously receive and process signals fromthe upper MEMS chip and the lower MEMS chip, and can also control theoperation of these MEMS chips. Therefore, the miniaturization of thepackage structure can be facilitated. In addition, in the packagestructure with MEMS device provided by the embodiment of the presentinvention, more than three MEMS chips with different functions may beintegrated in the same package structure without significantlyincreasing the area of the package structure. Therefore, the applicationfields of the package structure with the MEMS device can be greatlyincreased under the premise of meeting the miniaturization of thepackage structure.

Although the disclosure has been described by way of example and interms of the preferred embodiments, it should be understood that variousmodifications and similar arrangements (as would be apparent to thoseskilled in the art) can be made herein without departing from the spiritand scope of the disclosure as defined by the appended claims.

What is claimed is:
 1. A package structure, comprising: a substratehaving a recess; a first microelectromechanical system (MEMS) chipformed on the substrate, wherein the first MEMS chip has athrough-substrate via, a lower surface of the first MEMS chip has afirst sensor or a microactuator, and the first sensor or themicroactuator is located in the recess; a first intermediate chip formedon the first MEMS chip, wherein the first intermediate chip has athrough-substrate via, the first intermediate chip comprises a signalconversion unit, a logic operation unit, a control unit, or acombination thereof; a second MEMS chip formed on the first intermediatechip, wherein the second MEMS chip has a through-substrate via, an uppersurface of the second MEMS chip has a second sensor or a microactuator,and the package structure comprises at least one of the first sensor andthe second sensor, and a first capping plate formed on the second MEMSchip, wherein the first capping plate provides a receiving space, andthe second sensor or the microactuator located on the upper surface ofthe second MEMS chip is located in the receiving space.
 2. The packagestructure as claimed in claim 1, further comprising: a secondintermediate chip formed between the first MEMS chip and the second MEMSchip, wherein the second intermediate chip has a through-substrate via,and the second intermediate chip comprises a memory unit, an antennaunit, or a combination thereof
 3. The package structure as claimed inclaim 2, further comprising: a third intermediate chip formed betweenthe first MEMS chip and the second MEMS chip, wherein the thirdintermediate chip has a through-substrate via, and the thirdintermediate chip comprises a memory unit, an antenna unit, or acombination thereof
 4. The package structure as claimed in claim 3,wherein the third intermediate chip and the second intermediate chip arehorizontally arranged.
 5. The package structure as claimed in claim 2,wherein the second intermediate chip and the first intermediate chip arehorizontally arranged.
 6. The package structure as claimed in claim 2,wherein the second intermediate chip is formed between the first MEMSchip and the first intermediate chip.
 7. The package structure asclaimed in claim 2, wherein the second intermediate chip is formedbetween the second MEMS chip and the first intermediate chip.
 8. Thepackage structure as claimed in claim 1, further comprising: a thirdMEMS chip formed on the first intermediate chip, and arrangedhorizontally with the second MEMS chip, wherein an upper surface of thethird MEMS chip has a third sensor or a microactuator; and a secondcapping plate formed on the third MEMS chip, wherein the third sensor orthe microactuator located on the upper surface of the third MEMS chip islocated in a receiving space provided by the second capping plate. 9.The package structure as claimed in claim 1, further comprising: a thirdMEMS chip formed between the first intermediate chip and the second MEMSchip, wherein an upper surface of the third MEMS chip has a third sensoror a microactuator; and a second capping plate formed on the third MEMSchip, wherein the third sensor or the microactuator located on the uppersurface of the third MEMS chip is located in a receiving space providedby the second capping plate.
 10. The package structure as claimed inclaim 9, wherein a sidewall of the second capping plate has an opening.11. The package structure as claimed in claim 1, further comprising: afirst redistribution layer formed between the first MEMS chip and thefirst intermediate chip; a second redistribution layer formed betweenthe first intermediate chip and the second MEMS chip; and a fillingmedium formed in at least one of the recess and the receiving space. 12.A method for manufacturing a package structure, comprising: providing asubstrate, wherein the substrate has a plurality of recesses; forming aplurality of first MEMS chips on the substrate, wherein each of thefirst MEMS chips has a through-substrate via, a lower surface of each ofthe first MEMS chips has a first sensor or microactuator, and the firstsensor or the microactuator is located in one of the recesses; forming aplurality of first intermediate chips on the substrate, wherein each ofthe first intermediate chips is respectively formed on one of the firstMEMS chips, wherein each of the first intermediate chips has athrough-substrate via, and wherein each of the first intermediate chipscomprises a signal conversion unit, a logic operation unit, a controlunit, or a combination thereof; forming a plurality of second MEMS chipson the first intermediate chips, wherein each of the second MEMS chipshas a through-substrate via, wherein an upper surface of each of thesecond MEMS chips has a second sensor or a microactuator, and whereinthe package structure comprises at least one of the first sensor and thesecond sensor; and forming a plurality of first capping plates on thesecond MEMS chips, wherein each of the first capping plates provides areceiving space, and wherein the second sensor or the microactuatorlocated on the upper surface of each of the second MEMS chips is locatedin the receiving space.
 13. The method for manufacturing the packagestructure as claimed in claim 12, further comprising: forming a firstmolding compound layer to cover the first MEMS chips; performing a firstplanarization process to expose upper surfaces of the first MEMS chips,so that the upper surfaces of the first MEMS chips and an upper surfaceof the first molding compound layer are coplanar; forming a firstredistribution layer on the first MEMS chip; forming a second moldingcompound layer to cover the first intermediate chips; performing asecond planarization process to expose upper surfaces of the firstintermediate chips, so that the upper surfaces of the first intermediatechips and an upper surface of the second molding compound layer arecoplanar; forming a second redistribution layer on the firstintermediate chip; and performing a cutting process on the firstredistribution layer, the first molding compound layer, the secondredistribution layer, the second molding compound layer, and thesubstrate.
 14. The method for manufacturing the package structure asclaimed in claim 12, further comprising: forming a second intermediatechip between the first MEMS chip and the second MEMS chip, wherein thesecond intermediate chip has a through-substrate via, and the secondintermediate chip comprises a memory unit, an antenna unit, or acombination thereof.
 15. The method for manufacturing the packagestructure as claimed in claim 14, further comprising: forming a thirdintermediate chip between the first MEMS chip and the second MEMS chip,wherein the third intermediate chip has a through-substrate via, and thethird intermediate chip comprises a memory unit, an antenna unit, or acombination thereof.
 16. The method for manufacturing the packagestructure as claimed in claim 12, forming a third MEMS chip on the firstintermediate chip and arranged horizontally with the second MEMS chip,wherein an upper surface of the third MEMS chip has a third sensor or amicroactuator; and forming a second capping plate on the third MEMSchip, wherein the third sensor or the microactuator located on the uppersurface of the third MEMS chip is located in a receiving space providedby the second capping plate.
 17. The method for manufacturing thepackage structure as claimed in claim 12, further comprising: forming athird MEMS chip between the first intermediate chip and the second MEMSchip, wherein an upper surface of the third MEMS chip has a third sensoror a microactuator; and forming a second capping plate on the third MEMSchip, wherein the third sensor or the microactuator located on the uppersurface of the third MEMS chip is located in a receiving space providedby the second capping plate.
 18. The method for manufacturing thepackage structure as claimed in claim 17, wherein a sidewall of thesecond capping plate has an opening.
 19. The method for manufacturingthe package structure as claimed in claim 12, further comprising:forming a first redistribution layer between the first MEMS chip and thefirst intermediate chip; forming a second redistribution layer betweenthe first intermediate chip and the second MEMS chip; and forming afilling medium in at least one of the recess and the receiving space.